The first patient to undergo a face transplant thanked her doctors as soon as she came round after the operation.
The patient was injured when her dog tried to wake her
The woman, who sustained her injuries when her dog mauled her is "doing well" and has been able to eat strawberries and chocolate, doctors say.
The medical team who carried out the operation on Sunday in Amiens, France, say they were justified in undertaking the ground-breaking surgery.
But one expert questioned if such a radical procedure was needed.
Laurent Lantieri, an advisor to the French National Consultative Ethics Committee, said the team who operated on the patient had violated the panel's advice by not attempting conventional reconstructive surgery first.
The team who carried out the pioneering operation - which altogether lasted around 21 hours - have been giving details of what they called an "exceptional case".
Facial tissue from a donor from Lille, who was brain-dead, was used to repair severe damage from the top of the woman's nose to her chin.
The medics denied reports she had been attacked while she was unconscious after a suicide attempt.
Transplant surgeon Dr Jean-Michel Dubernard said the woman had taken a pill to try to sleep after a family argument, and was bitten by her dog during the night.
"There was no suicide".
The pet was later put down, against the family's wishes.
Dr Dubernard said several psychiatrists had assessed the patient before her operation and "all gave the green light".
Dr Bernard Devauchelle, a facial surgeon who took part in the operation, said: "We decided to go ahead with a transplant of part of the face because it restored the anatomy and the aesthetics, but also the function of this face."
Philippe Domy, the director of the hospital in Amiens, northern France, where the transplant was carried out last Sunday said the surgery was required because the patient's case was exceptional.
"We are in an exceptional situation that required an exceptional response," he said.
Dr Devauchelle described how the team painstakingly transplanted skin, muscle tissue - connecting lots of blood vessels and nerve cells.
Connecting the nerves should allow the patient's face to be mobile, he said.
Four hours after the operation, blood was flowing through the transplanted tissue.
The patient regained consciousness 24 hours after the operation.
Caroline Camby, director general of the agency under the French health ministry that co-ordinates organ procurement, said normal surgery had not been possible in this case.
"It is precisely because there was no way to restore the functions of this patient by normal plastic surgery that we attempted this transplant.
"She could no longer eat normally, she had great difficulty speaking and there is no possibility with plastic surgery today to repair muscles around the mouth which allow people to articulate when they speak and not spit out food when they eat."
It has been technically possible to carry out such a transplant for some years, with teams in the US, the UK and France researching the procedure.
But the ethical concerns of a face transplant, and the psychological impact to the patient of looking different has held teams back.
There have also been concerns about the consequences of patients having to take to immunosuppressant drugs for the rest of their lives.
1 Triangle of skin and muscle tissue is cut away from donor's face
2 Blood vessels and nerves from face section are connected to recipient using microvascular surgery